Quantitative analysis, validation, and application of an LC-MS/MS method for four artificial sweeteners in dairy-based foods and beverages

This study aimed to validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and optimize a sample preparation procedure for the analysis of four artificial sweeteners—acesulfame potassium, sodium saccharin, sucralose, and aspartame—in dairy matrices. The method demonstrated high specificity and excellent linearity (r² ≥ 0.999). The LOD values ranged from 0.002 to 0.103 mg/L, and the LOQ values ranged from 0.007 to 0.312 mg/L. The method’s accuracy was 84.40%–103.97%, and the precision was within a relative standard deviation (RSD) of 6.67%. All these results met both the AOAC and ICH guidelines. Minimal matrix effects (within ± 10%) ensured reliable quantification, while optimal recovery was achieved by using 0.6 mL each of potassium ferrocyanide trihydrate and zinc sulfate heptahydrate for deproteinization. Inter-laboratory validation showed recovery rates of 90.89%–102.74% with ≤ 7.78% RSD, supporting the robustness of the method. The validated method was applied to 40 dairy product samples, including fermented milk, processed milk, thick fermented milk, and lactic acid bacteria beverages. The detected concentrations of acesulfame potassium and sucralose complied with the Korean Food Code limits, respectively. Sodium saccharin was not detected in any samples, consistent with its prohibition. Aspartame was detected only in fermented milk, with concentrations of 65.08–269.42 mg/kg. The validated method reliably assessed compliance with national standards for artificial sweeteners and demonstrated suitability for monitoring artificial sweeteners in dairy products.